1. Field of the Invention
The present invention relates to apparatuses that include connectors that are configured to automatically connect and disconnect peripheral devices to and from the apparatuses. More particularly, the present invention relates to apparatuses such as portable information devices, like a portable personal computer, etc., that includes a locking/unlocking mechanism that facilitates connection with a peripheral alternating current (AC) adapter, which provides direct current (DC) power to the respective apparatuses.
2. Description of Background
Portable personal computers include an internal power source in the form of a battery that provides DC power used to operate the portable personal computers. These personal computers include an external (i.e., auxiliary or peripheral) AC adapter that provides the personal computer with a source of DC power, in the form of an electrical current. The DC power source recharges the internal battery and/or provides the primary power source for operating the personal computer. Connection between the AC adapter and the portable personal computer is accomplished by inserting a DC connector portion of the AC adapter into a female connector (i.e., a receptacle) formed in a body of the personal computer.
When the female connector receives the DC connector, the DC connector is held in place by a frictional force between the female connector and the DC connector. The frictional force is often insufficient to hold the two connectors in place, and if inadvertently bumped or jostled, may result in loss of power (and perhaps loss of data) as a result of the two connectors becoming disconnected from one another.
FIG. 8 is derived from Japanese patent application laid open (KOKAI) No 7-141059 and shows an example background art locking mechanism that is configured to prevent an inadvertent disconnection of the DC connector. FIG. 8 is a detailed view showing a conventional AC adapter assembly having an AC adapter portion 81 and a DC connector 82. A locking mechanism 83 is included in the DC connector 82 to prevent the DC connector 82 from inadvertently becoming detached from a personal computer or the like. Removal of the DC connector 82 requires a user to depress a button 83a which lowers a locking switch 84 that interlocks with a female connector portion of the personal computer. Without depressing the button 83a, the DC connector 82 cannot be removed from the female connector.
As identified by the present inventors, the conventional locking mechanism if the DC connector 82 is large and complex. Furthermore the AC adapter portion supplies an electric power to the personal computer via the female connector even if the power to the personal computer is turned off, thus wasting energy by perpetually attempting to maintain a peak charge in the internal battery at all times.
FIG. 9 is a schematic block diagram of the device shown in FIG. 8. The DC connector 82 is shown connecting to an apparatus 100. A cable 106 carries a ground line (GND) and a DC line (+DC). The cable 106 connects the AC adapter 81 to the DC connector 82. Within the AC adapter 81, a control circuit 102 is connected to a rectifier 104 that rectifies an AC an provides an output DC voltage on the DC line (+DC). The control circuit 102 connects to a third conductor which is shown contacting the GND line via the locking switch 84. The control circuit 102 senses when the DC connector connects to the apparatus 100 via the locking switch 84 and controls a switch 108 to close when contact is made.
One limitation with this conventional device is that it will allow power to be drawn to the apparatus 100 even if the main power switch to the apparatus 100 is turned off. Another limitation is that every connector 82 that connects to the body 100 must have a complex mechanism that includes the button 83a. Furthermore, contact is only made at the single location of the locking switch 84, and thus the integrity of this connection depends upon the button 83a maintaining its resiliency.
Consequently, the present inventors have determined that a need exists for a compact locking mechanism that automatically locks and unlocks a DC connector portion (having a simplified structure) of an AC adapter when a device to which the AC adapter is connected, is turned ON and OFF, respectively. Furthermore, the present inventors have determined a need exists for identifying an AC adapter that does not draw AC power when the device is not being used (i.e., not turned-ON).